1
|
Qubad M, Dupont G, Hahn M, Martin SS, Puntmann V, Nagel E, Reif A, Bittner RA. When, Why and How to Re-challenge Clozapine in Schizophrenia Following Myocarditis. CNS Drugs 2024:10.1007/s40263-024-01100-4. [PMID: 38951464 DOI: 10.1007/s40263-024-01100-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/03/2024] [Indexed: 07/03/2024]
Abstract
Clozapine-induced myocarditis (CIM) is among the most important adverse events limiting the use of clozapine as the most effective treatment for schizophrenia. CIM necessitates the immediate termination of clozapine, often resulting in its permanent discontinuation with considerable detrimental effects on patients' psychopathology and long-term outcome. Consequently, a clozapine re-challenge after CIM is increasingly regarded as a viable alternative, with published reports indicating a success rate of approximately 60%. However, published cases of re-challenges after CIM remain limited. Here, we provide a narrative review of the current state of research regarding the epidemiology, pathophysiology, risk factors, diagnosis and clinical management of CIM as well as a synthesis of current recommendations for re-challenging patients after CIM. This includes a step-by-step guide for this crucial procedure based on the current evidence regarding the pathophysiology and risk factors for CIM. Slow dose titration regimes and addressing risk factors including concomitant valproate and olanzapine are crucial both to prevent CIM and to ensure a safe and successful re-challenge. Furthermore, we discuss the utility of C-reactive protein, troponin, N-terminal-pro hormone and brain natriuretic peptide, therapeutic drug-monitoring and cardiac magnetic resonance imaging for CIM screening and diagnosis as well as for post-CIM re-challenges.
Collapse
Affiliation(s)
- Mishal Qubad
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University Frankfurt, University Hospital, Frankfurt, Germany.
| | - Gabriele Dupont
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University Frankfurt, University Hospital, Frankfurt, Germany
| | - Martina Hahn
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University Frankfurt, University Hospital, Frankfurt, Germany
- Department of Mental Health, Varisano Hospital Frankfurt Hoechst, Frankfurt, Germany
| | - Simon S Martin
- Department of Radiology, Goethe University Frankfurt, University Hospital, Frankfurt, Germany
| | - Valentina Puntmann
- Department of Cardiology, Institute for Experimental and Translational Cardiovascular Imaging, Goethe University Frankfurt, University Hospital, Frankfurt, Germany
| | - Eike Nagel
- Department of Cardiology, Institute for Experimental and Translational Cardiovascular Imaging, Goethe University Frankfurt, University Hospital, Frankfurt, Germany
| | - Andreas Reif
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University Frankfurt, University Hospital, Frankfurt, Germany
| | - Robert A Bittner
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University Frankfurt, University Hospital, Frankfurt, Germany.
- Ernst Strüngmann Institute for Neuroscience (ESI) in Cooperation with Max Planck Society, Frankfurt, Germany.
| |
Collapse
|
2
|
Qi L, Ma B, Fan H, Qi S, Yang F, An H. Case report: Time response of plasma clozapine concentrations on cessation of heavy smoking. Front Pharmacol 2024; 15:1408915. [PMID: 38974031 PMCID: PMC11224526 DOI: 10.3389/fphar.2024.1408915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Accepted: 06/05/2024] [Indexed: 07/09/2024] Open
Abstract
Smoking cessation in patients treated with clozapine might lead to elevated plasma concentrations and severe side effects. This case report investigated the trajectory of clozapine plasma concentrations over time after smoking cessation in a Chinese inpatient with schizophrenia. This case report delineates the temporal response of plasma clozapine concentrations and dose-corrected clozapine plasma concentrations in a 33-year-old inpatient with schizophrenia who had a substantial smoking history and ceased smoking abruptly during dose titration. This case report presents a sudden increase in plasma clozapine concentrations and dose-corrected plasma clozapine concentrations after smoking cessation, followed by a rapid decline in dose-corrected plasma clozapine concentrations during the initial 2 weeks and a return to pre-cessation levels approximately 1 month later. The findings suggest that clinicians and pharmacists should adjust clozapine dosage in accordance with changes in smoking status, taking into consideration the temporal effects. Post-smoking cessation adjustments to clozapine dosage should be coupled with therapeutic drug monitoring, especially for patients with heavy smoking habits. Moreover, the advice of the clinical pharmacist should be considered in complex cases to ensure safe use of clozapine.
Collapse
Affiliation(s)
| | | | | | | | - Fude Yang
- Peking University, HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, China
| | - Huimei An
- Peking University, HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Beijing, China
| |
Collapse
|
3
|
Bellissima BL, Burns KE, Helsby NA, Kingston EL, Garavan F, Tingle MD. Clozapine metabolism and cardiotoxicity: A prospective longitudinal study. Int J Cardiol 2024; 403:131788. [PMID: 38244893 DOI: 10.1016/j.ijcard.2024.131788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 12/19/2023] [Accepted: 01/14/2024] [Indexed: 01/22/2024]
Abstract
BACKGROUND Clozapine-induced myocarditis and cardiomyopathy are difficult to detect clinically and may be fatal if not detected early. The current/routine biomarkers for clozapine-induced myocarditis are non-specific indicators of inflammation (C-reactive protein) or cardiomyocyte damage (troponins I and T) that lack sensitivity, and for which changes often arise too late to be clinically useful. METHODS The Clozapine Safety Study was a prospective, longitudinal, observational study to determine what, if any, the plasma concentrations of clozapine, N-desmethylclozapine, and clozapine-N-oxide in patients contribute to cardiotoxicity. Samples were collected and analysed using liquid chromatography mass spectrometry over a 41-month period from patients in the Auckland District Health Board. RESULTS Sixty-seven patients were included. Six patients were diagnosed with myocarditis; none were diagnosed with cardiomyopathy in the study period. In patients not undergoing dose titration, clozapine biotransformation may shift to the N-oxide pathway rather than the N-desmethyl pathway with increasing dose. During dose titration, the timeframe in which myocarditis occurs, the rate of increase in the plasma concentration of clozapine-N-oxide, as well as the ratio of N-oxidation relative to N-desmethylation, were significantly higher in patients diagnosed with myocarditis. CONCLUSIONS The assessment of clozapine-N-oxide formation, and N-oxidation relative to N-desmethylation ratios during treatment, may help identify a biomarker to aid the early detection of patients at risk of developing clozapine-induced cardiotoxicity.
Collapse
Affiliation(s)
- Brandi L Bellissima
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Kathryn E Burns
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Nuala A Helsby
- Department of Molecular Medicine and Pathology, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Ellen L Kingston
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Fintan Garavan
- Department of Forensic Pathology, Auckland District Health Board, LabPLUS, Auckland City Hospital, Gate 4, Grafton Road, PO Box 110031, Auckland, New Zealand.
| | - Malcom D Tingle
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| |
Collapse
|
4
|
Wiss FM, Allemann SS, Meyer zu Schwabedissen HE, Stäuble CK, Mikoteit T, Lampert ML. Recurrent high creatine kinase levels under clozapine treatment - a case report assessing a suspected adverse drug reaction. Front Psychiatry 2024; 15:1397876. [PMID: 38742124 PMCID: PMC11089194 DOI: 10.3389/fpsyt.2024.1397876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 04/02/2024] [Indexed: 05/16/2024] Open
Abstract
Suspected adverse drug reactions (ADRs) during treatment with clozapine often prompt therapeutic drug monitoring (TDM) in clinical practice. Currently, there is no official recommendation for pharmacogenetic (PGx) testing in the context of clozapine therapy. In this case report, we demonstrate and discuss the challenges of interpreting PGx and TDM results highlighting the possibilities and limitations of both analytical methods. A 36-year-old male patient with catatonic schizophrenia was treated with clozapine. He experienced multiple hospitalizations due to elevated creatine kinase (CK) levels (up to 9000 U/L, reference range: 30-200 U/L). With no other medical explanation found, physicians suspected clozapine-induced ADRs. However, plasma levels of clozapine were consistently low or subtherapeutic upon admission, prompting us to conduct a PGx analysis and retrospectively review the patient's TDM data, progress notes, and discharge reports. We investigated two possible hypotheses to explain the symptoms despite low clozapine plasma levels: Hypothesis i. suggested the formation and accumulation of a reactive intermediate metabolite due to increased activity in cytochrome P450 3A5 and reduced activity in glutathione S-transferases 1, leading to myotoxicity. Hypothesis ii. proposed under-treatment with clozapine, resulting in ineffective clozapine levels, leading to a rebound effect with increased catatonic symptoms and CK levels. After considering both data sources (PGx and TDM), hypothesis ii. appeared more plausible. By comprehensively assessing all available TDM measurements and examining them in temporal correlation with the drug dose and clinical symptoms, we observed that CK levels normalized when clozapine plasma levels were raised to the therapeutic range. This was achieved through hospitalization and closely monitored clozapine intake. Therefore, we concluded that the symptoms were not an ADR due to altered clozapine metabolism but rather the result of under-treatment. Interpreting TDM and PGx results requires caution. Relying solely on isolated PGx or single TDM values can result in misinterpretation of drug reactions. We recommend considering the comprehensive patient history, including treatment, dosages, laboratory values, clinic visits, and medication adherence.
Collapse
Affiliation(s)
- Florine M. Wiss
- Pharmaceutical Care, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
- Institute of Hospital Pharmacy, Solothurner Spitäler, Olten, Switzerland
| | - Samuel S. Allemann
- Pharmaceutical Care, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | | | - Céline K. Stäuble
- Pharmaceutical Care, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
- Institute of Hospital Pharmacy, Solothurner Spitäler, Olten, Switzerland
- Biopharmacy, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Thorsten Mikoteit
- Psychiatric Services Solothurn, Solothurner Spitäler and Department of Medicine, University of Basel, Solothurn, Switzerland
| | - Markus L. Lampert
- Pharmaceutical Care, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
- Institute of Hospital Pharmacy, Solothurner Spitäler, Olten, Switzerland
| |
Collapse
|
5
|
Jurva U, Sandinge AS, Baek JM, Avanthay M, Thomson RES, D'Cunha SA, Andersson S, Hayes MA, Gillam EMJ. Biocatalysis using Thermostable Cytochrome P450 Enzymes in Bacterial Membranes - Comparison of Metabolic Pathways with Human Liver Microsomes and Recombinant Human Enzymes. Drug Metab Dispos 2024; 52:242-251. [PMID: 38176735 DOI: 10.1124/dmd.123.001569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 01/06/2024] Open
Abstract
Detailed structural characterization of small molecule metabolites is desirable during all stages of drug development, and often relies on the synthesis of metabolite standards. However, introducing structural changes into already complex, highly functionalized small molecules both regio- and stereo-selectively can be challenging using purely chemical approaches, introducing delays into the drug pipeline. An alternative is to use the cytochrome P450 enzymes (P450s) that produce the metabolites in vivo, taking advantage of the enzyme's inherently chiral active site to achieve regio- and stereoselectivity. Importantly, biotransformations are more sustainable: they proceed under mild conditions and avoid environmentally damaging solvents and transition metal catalysts. Recombinant enzymes avoid the need to use animal liver microsomes. However, native enzymes must be stabilized to work for extended periods or at elevated temperatures, and stabilizing mutations can alter catalytic activity. Here we assessed a set of novel, thermostable P450s in bacterial membranes, a format analogous to liver microsomes, for their ability to metabolize drugs through various pathways and compared them to human liver microsomes. Collectively, the thermostable P450s could replicate the metabolic pathways seen with human liver microsomes, including bioactivation to protein-reactive intermediates. Novel metabolites were found, suggesting the possibility of obtaining metabolites not produced by human or rodent liver microsomes. Importantly, no alteration in assay conditions from standard protocols for microsomal incubations was necessary. Thus, such bacterial membranes represent an analogous metabolite generation system to liver microsomes in terms of metabolites produced and ease of use, but which provides access to more diversity of metabolite structures. SIGNIFICANCE STATEMENT: In drug development it is often chemically challenging, to synthesize authentic metabolites of drug candidates for structural identification and evaluation of activity and safety. Biosynthesis using microsomes or recombinant human enzymes is confounded by the instability of the enzymes. Here we show that thermostable ancestral cytochrome P450 enzymes derived from P450 families responsible for human drug metabolism offer advantages over the native human forms in being more robust and over microbial enzymes in faithfully reflecting human drug metabolism.
Collapse
Affiliation(s)
- Ulrik Jurva
- Drug Metabolism and Pharmacokinetics (DMPK), Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (U.J., A.-S.S.); School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, 4072, Australia (J.M.B., R.E.S.T., S.A.D.C., E.M.J.G.); and Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (M.A., S.A., M.A.H.)
| | - Ann-Sofie Sandinge
- Drug Metabolism and Pharmacokinetics (DMPK), Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (U.J., A.-S.S.); School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, 4072, Australia (J.M.B., R.E.S.T., S.A.D.C., E.M.J.G.); and Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (M.A., S.A., M.A.H.)
| | - Jong Min Baek
- Drug Metabolism and Pharmacokinetics (DMPK), Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (U.J., A.-S.S.); School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, 4072, Australia (J.M.B., R.E.S.T., S.A.D.C., E.M.J.G.); and Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (M.A., S.A., M.A.H.)
| | - Mickaël Avanthay
- Drug Metabolism and Pharmacokinetics (DMPK), Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (U.J., A.-S.S.); School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, 4072, Australia (J.M.B., R.E.S.T., S.A.D.C., E.M.J.G.); and Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (M.A., S.A., M.A.H.)
| | - Raine E S Thomson
- Drug Metabolism and Pharmacokinetics (DMPK), Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (U.J., A.-S.S.); School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, 4072, Australia (J.M.B., R.E.S.T., S.A.D.C., E.M.J.G.); and Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (M.A., S.A., M.A.H.)
| | - Stephlina A D'Cunha
- Drug Metabolism and Pharmacokinetics (DMPK), Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (U.J., A.-S.S.); School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, 4072, Australia (J.M.B., R.E.S.T., S.A.D.C., E.M.J.G.); and Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (M.A., S.A., M.A.H.)
| | - Shalini Andersson
- Drug Metabolism and Pharmacokinetics (DMPK), Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (U.J., A.-S.S.); School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, 4072, Australia (J.M.B., R.E.S.T., S.A.D.C., E.M.J.G.); and Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (M.A., S.A., M.A.H.)
| | - Martin A Hayes
- Drug Metabolism and Pharmacokinetics (DMPK), Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (U.J., A.-S.S.); School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, 4072, Australia (J.M.B., R.E.S.T., S.A.D.C., E.M.J.G.); and Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (M.A., S.A., M.A.H.)
| | - Elizabeth M J Gillam
- Drug Metabolism and Pharmacokinetics (DMPK), Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (U.J., A.-S.S.); School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, 4072, Australia (J.M.B., R.E.S.T., S.A.D.C., E.M.J.G.); and Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden (M.A., S.A., M.A.H.)
| |
Collapse
|
6
|
Kingston E, Tingle M, Bellissima BL, Helsby N, Burns K. CYP-catalysed cycling of clozapine and clozapine- N-oxide promotes the generation of reactive oxygen species in vitro. Xenobiotica 2024; 54:26-37. [PMID: 38108307 DOI: 10.1080/00498254.2023.2294473] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/10/2023] [Indexed: 12/19/2023]
Abstract
Clozapine is an effective atypical antipsychotic indicated for treatment-resistant schizophrenia, but is under-prescribed due to the risk of severe adverse drug reactions such as myocarditis.A mechanistic understanding of clozapine cardiotoxicity remains elusive.This study aimed to investigate the contribution of selected CYP isoforms to cycling between clozapine and its major circulating metabolites, N-desmethylclozapine and clozapine-N-oxide, with the potential for reactive species production.CYP supersome™-based in vitro techniques were utilised to quantify specific enzyme activity associated with clozapine, clozapine-N-oxide and N-desmethylclozapine metabolism.The formation of reactive species within each incubation were quantified, and known intermediates detected.CYP3A4 predominately catalysed clozapine-N-oxide formation from clozapine and was associated with concentration-dependent reactive species production, whereas isoforms favouring the N-desmethylclozapine pathway (CYP2C19 and CYP1A2) did not produce reactive species.Extrahepatic isoforms CYP2J2 and CYP1B1 were also associated with the formation of clozapine-N-oxide and N-desmethylclozapine but did not favour one metabolic pathway over another.Unique to this investigation is that various CYP isoforms catalyse clozapine-N-oxide reduction to clozapine.This process was associated with the concentration-dependent formation of reactive species with CYP3A4, CYP1B1 and CYP1A1 that did not correlate with known reactive intermediates, implicating metabolite cycling and reactive oxygen species in the mechanism of clozapine-induced toxicity.
Collapse
Affiliation(s)
- Ellen Kingston
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Auckland, New Zealand
| | - Malcolm Tingle
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Auckland, New Zealand
| | - Brandi L Bellissima
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Auckland, New Zealand
| | - Nuala Helsby
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Kathryn Burns
- Department of Pharmacology and Clinical Pharmacology, The University of Auckland, Auckland, New Zealand
| |
Collapse
|
7
|
Watanabe K, Misaka S, Kanno-Nozaki K, Chiyoda T, Suzuki Y, Sato A, Suto T, Kuroda J, Shimomura K, Miura I, Yabe H. Effect of lemborexant on pharmacokinetics of clozapine: A potential drug-drug interaction mediated by time-dependent inhibition of CYP3A4. Br J Clin Pharmacol 2024; 90:354-359. [PMID: 37596710 DOI: 10.1111/bcp.15889] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/02/2023] [Accepted: 08/09/2023] [Indexed: 08/20/2023] Open
Abstract
Clozapine (CLZ) is extensively used for treatment-resistant schizophrenia (TRS) with caution to avoid serious adverse events such as agranulocytosis and drug-drug interactions (DDIs). In the current report, we present a case of a 35-year-old male non-smoking TRS patient whose steady-state plasma trough concentrations (Ctrough ) of CLZ and its active metabolite, N-desmethylclozapine (NDMC), were significantly increased after initiating oral administration of lemborexant (LEM), a dual orexin receptor antagonist, for the treatment of insomnia. The patient experienced oversedation with sleepiness and fatigue while maintaining high levels of Ctrough of CLZ. The increased concentrations of CLZ returned to normal ranges after the discontinuation of LEM dosing, implying a pharmacokinetic DDI between CLZ and LEM. To gain insight into possible mechanisms, we performed in vitro assays of CYP1A2- and CYP3A4-mediated CLZ metabolism by measuring the formations of NDMC and clozapine N-oxide (CNO). In accordance with previous studies, the incubation of CLZ with each enzyme resulted in the production of both metabolites. LEM had only a weak inhibitory effect on CYP1A2- and CYP3A4-mediated CLZ metabolism. However, the preincubation of LEM with CYP3A4 in the presence of NADPH showed a significant enhancement of inhibitory effects on CLZ metabolism with IC50 values for the formations of CNO and NDMC of 2.8 μM and 4.1 μM, respectively, suggesting that LEM exerts as a potent time-dependent inhibitor for CYP3A4. Taken together, the results of the current study indicate that co-medication of CLZ with LEM may lead to increase in exposure to CLZ and risks of CLZ-related adverse events.
Collapse
Affiliation(s)
- Kenya Watanabe
- Department of Pharmacy, Fukushima Medical University Hospital, Fukushima, Japan
| | - Shingen Misaka
- Department of Pharmacy, Fukushima Medical University Hospital, Fukushima, Japan
- Department of Bioregulation and Pharmacological Medicine, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Keiko Kanno-Nozaki
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Takaaki Chiyoda
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Yuhei Suzuki
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Akiko Sato
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Takahiro Suto
- Department of Pharmacy, Fukushima Medical University Hospital, Fukushima, Japan
| | - Junko Kuroda
- Department of Pharmacy, Fukushima Medical University Hospital, Fukushima, Japan
| | - Kenju Shimomura
- Department of Bioregulation and Pharmacological Medicine, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Itaru Miura
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Hirooki Yabe
- Department of Neuropsychiatry, School of Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| |
Collapse
|
8
|
Rosell-Hidalgo A, Eakins J, Walker P, Moore AL, Ghafourian T. Risk Assessment of Psychotropic Drugs on Mitochondrial Function Using In Vitro Assays. Biomedicines 2023; 11:3272. [PMID: 38137493 PMCID: PMC10741027 DOI: 10.3390/biomedicines11123272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 11/30/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023] Open
Abstract
Mitochondria are potential targets responsible for some drug- and xenobiotic-induced organ toxicities. However, molecular mechanisms of drug-induced mitochondrial toxicities are mostly unknown. Here, multiple in vitro assays were used to investigate the effects of 22 psychotropic drugs on mitochondrial function. The acute extracellular flux assay identified inhibitors of the electron transport chain (ETC), i.e., aripiprazole, phenytoin, and fluoxetine, an uncoupler (reserpine), substrate inhibitors (quetiapine, carbamazepine, buspirone, and tianeptine), and cytotoxic compounds (chlorpromazine and valproic acid) in HepG2 cells. Using permeabilized HepG2 cells revealed minimum effective concentrations of 66.3, 6730, 44.5, and 72.1 µM for the inhibition of complex-I-linked respiration for quetiapine, valproic acid, buspirone, and fluoxetine, respectively. Assessing complex-II-linked respiration in isolated rat liver mitochondria revealed haloperidol is an ETC inhibitor, chlorpromazine is an uncoupler in basal respiration and an ETC inhibitor under uncoupled respiration (IC50 = 135 µM), while olanzapine causes a mild dissipation of the membrane potential at 50 µM. This research elucidates some mechanisms of drug toxicity and provides some insight into their safety profile for clinical drug decisions.
Collapse
Affiliation(s)
- Alicia Rosell-Hidalgo
- Cyprotex Discovery Ltd., No. 24 Mereside, Alderley Park, Macclesfield, Cheshire SK10 4TG, UK; (A.R.-H.); (J.E.)
| | - Julie Eakins
- Cyprotex Discovery Ltd., No. 24 Mereside, Alderley Park, Macclesfield, Cheshire SK10 4TG, UK; (A.R.-H.); (J.E.)
| | - Paul Walker
- Cyprotex Discovery Ltd., No. 24 Mereside, Alderley Park, Macclesfield, Cheshire SK10 4TG, UK; (A.R.-H.); (J.E.)
| | - Anthony L. Moore
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK;
| | - Taravat Ghafourian
- Department of Pharmaceutical Sciences, Barry & Judy Silverman College of Pharmacy, Nova Southeastern University, 3200 South University Drive, Ft. Lauderdale, FL 33328-2018, USA
| |
Collapse
|
9
|
Ma B, Fan H, Qi S, Yang F, An H. Effects of smoking cessation on plasma clozapine concentrations in male patients with schizophrenia during the COVID-19 pandemic. Front Psychiatry 2023; 14:1256264. [PMID: 37779619 PMCID: PMC10541223 DOI: 10.3389/fpsyt.2023.1256264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/30/2023] [Indexed: 10/03/2023] Open
Abstract
Introduction This study aimed to investigate the effect of smoking cessation on plasma clozapine (CLO) concentrations in long-term hospitalized Chinese male patients with schizophrenia treated with CLO during the COVID-19 pandemic. Methods Therapeutic drug monitoring (TDM) data for CLO were collected at Beijing HuiLongGuan Hospital between December 1, 2019 (before smoking cessation) and January 31, 2020 (after smoking cessation) in this retrospective study. Fifty-three male smokers and inpatients with schizophrenia who were treated with CLO were included. Plasma concentrations of CLO were measured using high-performance liquid chromatography-tandem mass spectrometry. The fagerstrom test for nicotine dependence (FTND) was used to assess smoking behavior. Results The plasma CLO concentrations and dose-corrected plasma CLO concentrations were significantly increased by 29.3 and 23.5%, respectively, after smoking cessation. Discussion The results suggested that clinicians and pharmacists should adjust the CLO dose based on changes in smoking status in patients stabilized with CLO during the COVID-19 pandemic. Careful TDM for CLO should be performed prior to dose adjustment,to reduce the increased risk of smoking cessation induced side effects, especially for older patients receiving multiple medications.
Collapse
Affiliation(s)
| | | | | | | | - Huimei An
- Psychiatry Research Center, HuiLongGuan Clinical Medical School, Beijing HuiLongGuan Hospital, Peking University, Beijing, China
| |
Collapse
|
10
|
Hong L. Bilateral Anterior Shoulder Dislocations Following a Clozapine-Induced Seizure. Cureus 2023; 15:e45778. [PMID: 37872936 PMCID: PMC10590618 DOI: 10.7759/cureus.45778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2023] [Indexed: 10/25/2023] Open
Abstract
Posterior shoulder dislocations are a recognised complication of generalised seizure episodes. Although less frequent, anterior shoulder dislocations are now being acknowledged as an emerging consequence. Particularly when they occur bilaterally, they can contribute to diagnosing a seizure disorder in a patient who shows no other signs during the post-ictal period. This article presents a case of bilateral anterior shoulder dislocations in an otherwise physically healthy young Sudanese gentleman following a generalised seizure episode on clozapine for a schizoaffective disorder. The case aims to raise awareness of the occurrence of this phenomenon and emphasises the importance of timely diagnostic testing, seizure prophylaxis, and follow-up to minimise the risk of further seizure episodes and potential consequences. Additionally, there is a discussion regarding the utility of monitoring clozapine concentrations.
Collapse
Affiliation(s)
- Lewis Hong
- Intensive Care Unit, Royal Perth Hospital, Perth, AUS
| |
Collapse
|
11
|
Demirbugen Oz M, Ozdemir F, Tok KC, Dural E, Kir Y, Ulusoy M, Gumustas M, Baskak B, Suzen HS. The potential role of por*28 and cyp1a2*f genetic variations and lifestyle factors on clozapine and n-desmethyl clozapine plasma levels in schizophrenia patients. Expert Opin Drug Metab Toxicol 2023. [PMID: 37269349 DOI: 10.1080/17425255.2023.2221849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/24/2023] [Indexed: 06/05/2023]
Abstract
BACKGROUND Despite its advantages over other antipsychotics, for treatment-resistant schizophrenia, clinical use of Clozapine (CLZ) is challenging by its narrow therapeutic index and potentially life-threatening dose-related adverse effects. RESEARCH DESIGN AND METHODS As the potential role in CLZ metabolism is assigned to CYP1A2 enzyme and consequently Cytochrome P450 oxidoreductase (POR) their genetic variations might help to determine CLZ levels in schizophrenia patients. For this purpose, 112 schizophrenia patients receiving CLZ were included in the current study. Plasma CLZ and N-desmethylclozapine (DCLZ) levels were analyzed by using HPLC and genetic variations were identified with the PCR-RFLP method. RESULTS The patients' CYP1A2 and POR genotypes seemed to not affect plasma CLZ and DCLZ levels whereas in the subgroup analysis, POR × 28 genotype significantly influenced simple and adjusted plasma CLZ and DLCZ levels concerning smoking habit and caffeine consumption. CONCLUSIONS The findings of the present study highlight the importance of both genetic and non-genetic factors (smoking and caffeine consumption) for the individualization of the CLZ treatment. In addition to that, it suggests that the added utility of not only the CLZ metabolizing enzymes but also POR, which is crucial for proper CYP activity, to guide CLZ dosing might be useful for clinical decision-making.
Collapse
Affiliation(s)
- Merve Demirbugen Oz
- Faculty of Pharmacy, Department of Pharmaceutical Toxicology, Ankara University, Ankara, Turkey
| | - Fezile Ozdemir
- Dr Fazil Kucuk Faculty of Medicine, Eastern Mediterranean University, North, Cyprus, Turkey
| | - Kenan Can Tok
- Institute of Forensic Sciences, Department of Forensic Toxicology, Ankara University, Ankara, Turkey
| | - Emrah Dural
- Faculty of Pharmacy, Department of Pharmaceutical Toxicology, Sivas Cumhuriyet University, Sivas, Turkey
| | - Yagmur Kir
- Bursa Acibadem Hospital, Department of Psychiatry, Bursa, Turkey
| | - Muge Ulusoy
- School of Medicine, Department of Psychiatry, Ankara University, Ankara, Turkey
| | - Mehmet Gumustas
- Institute of Forensic Sciences, Department of Forensic Toxicology, Ankara University, Ankara, Turkey
| | - Bora Baskak
- School of Medicine, Department of Psychiatry, Ankara University, Ankara, Turkey
| | - H Sinan Suzen
- Faculty of Pharmacy, Department of Pharmaceutical Toxicology, Ankara University, Ankara, Turkey
| |
Collapse
|
12
|
Marie S, Frost KL, Hau RK, Martinez-Guerrero L, Izu JM, Myers CM, Wright SH, Cherrington NJ. Predicting disruptions to drug pharmacokinetics and the risk of adverse drug reactions in non-alcoholic steatohepatitis patients. Acta Pharm Sin B 2023; 13:1-28. [PMID: 36815037 PMCID: PMC9939324 DOI: 10.1016/j.apsb.2022.08.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/29/2022] [Accepted: 08/03/2022] [Indexed: 12/18/2022] Open
Abstract
The liver plays a central role in the pharmacokinetics of drugs through drug metabolizing enzymes and transporters. Non-alcoholic steatohepatitis (NASH) causes disease-specific alterations to the absorption, distribution, metabolism, and excretion (ADME) processes, including a decrease in protein expression of basolateral uptake transporters, an increase in efflux transporters, and modifications to enzyme activity. This can result in increased drug exposure and adverse drug reactions (ADRs). Our goal was to predict drugs that pose increased risks for ADRs in NASH patients. Bibliographic research identified 71 drugs with reported ADRs in patients with liver disease, mainly non-alcoholic fatty liver disease (NAFLD), 54 of which are known substrates of transporters and/or metabolizing enzymes. Since NASH is the progressive form of NAFLD but is most frequently undiagnosed, we identified other drugs at risk based on NASH-specific alterations to ADME processes. Here, we present another list of 71 drugs at risk of pharmacokinetic disruption in NASH, based on their transport and/or metabolism processes. It encompasses drugs from various pharmacological classes for which ADRs may occur when used in NASH patients, especially when eliminated through multiple pathways altered by the disease. Therefore, these results may inform clinicians regarding the selection of drugs for use in NASH patients.
Collapse
Affiliation(s)
- Solène Marie
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Kayla L. Frost
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Raymond K. Hau
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Lucy Martinez-Guerrero
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Jailyn M. Izu
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Cassandra M. Myers
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA
| | - Stephen H. Wright
- College of Medicine, Department of Physiology, University of Arizona, Tucson, AZ 85724, USA
| | - Nathan J. Cherrington
- College of Pharmacy, Department of Pharmacology & Toxicology, University of Arizona, Tucson, AZ 85721, USA,Corresponding author. Tel.: +1 520 6260219; fax: +1 520 6266944.
| |
Collapse
|
13
|
Racial/Ethnic Differences in the Pharmacokinetics of Antipsychotics: Focusing on East Asians. J Pers Med 2022; 12:jpm12091362. [PMID: 36143147 PMCID: PMC9504618 DOI: 10.3390/jpm12091362] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 11/17/2022] Open
Abstract
Empirical clinical studies have suggested that East Asian patients may require lower dosages of psychotropic drugs, such as antipsychotics, lithium, and antidepressants, than non-Asians. Both the pharmacokinetic and pharmacodynamic properties of a drug can affect the clinical response of an illness. The levels of antipsychotics used for the treatment of schizophrenia may affect patient clinical responses; several factors can affect these levels, including patient medication adherence, body weight (BW) or body mass index, smoking habits, and sex. The cytochrome P450 (CYP) system is a major factor affecting the blood levels of antipsychotics because many antipsychotics are metabolized by this system. There were notable genetic differences between people of different races. In this study, we determined the racial or ethnic differences in the metabolic patterns of some selected antipsychotics by reviewing therapeutic drug monitoring studies in East Asian populations. The plasma concentrations of haloperidol, clozapine, quetiapine, aripiprazole, and lurasidone, which are metabolized by specific CYP enzymes, were determined to be higher, under the same daily dose, in East Asian populations than in Western populations.
Collapse
|
14
|
Jackson KD, Argikar UA, Cho S, Crouch RD, Driscoll JP, Heck C, King L, Maw HH, Miller GP, Seneviratne HK, Wang S, Wei C, Zhang D, Khojasteh SC. Bioactivation and Reactivity Research Advances - 2021 year in review. Drug Metab Rev 2022; 54:246-281. [PMID: 35876116 DOI: 10.1080/03602532.2022.2097254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This year's review on bioactivation and reactivity began as a part of the annual review on biotransformation and bioactivation led by Cyrus Khojasteh (Khojasteh et al., 2021, 2020, 2019, 2018, 2017; Baillie et al., 2016). Increased contributions from experts in the field led to the development of a stand alone edition for the first time this year focused specifically on bioactivation and reactivity. Our objective for this review is to highlight and share articles which we deem influential and significant regarding the development of covalent inhibitors, mechanisms of reactive metabolite formation, enzyme inactivation, and drug safety. Based on the selected articles, we created two sections: (1) reactivity and enzyme inactivation, and (2) bioactivation mechanisms and safety (Table 1). Several biotransformation experts have contributed to this effort from academic and industry settings.
Collapse
Affiliation(s)
- Klarissa D Jackson
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, Chapel Hill, NC 27599, USA
| | - Upendra A Argikar
- Non-clinical Development, Bill & Melinda Gates Medical Research Institute, Cambridge, MA, 02139, USA
| | - Sungjoon Cho
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco, CA, 94080, USA
| | - Rachel D Crouch
- Department of Pharmaceutical Sciences, Lipscomb University College of Pharmacy and Health Sciences, Nashville, TN, 37203, USA
| | - James P Driscoll
- Department of Drug Metabolism and Pharmacokinetics. Bristol Myers Squibb, Brisbane, CA, 94005, USA
| | - Carley Heck
- Medicine Design, Pfizer Worldwide Research, Development and Medical, Eastern Point Road, Groton, Connecticut, USA
| | - Lloyd King
- Department of DMPK, UCB Biopharma UK, 216 Bath Road, Slough, SL1 3WE, UK
| | - Hlaing Holly Maw
- Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT, 06877, USA
| | - Grover P Miller
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, 4301 W Markham St Slot 516, Little Rock, Arkansas, 72205, USA
| | - Herana Kamal Seneviratne
- Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Shuai Wang
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco, CA, 94080, USA
| | - Cong Wei
- Drug Metabolism & Pharmacokinetics, Biogen Inc., Cambridge, MA, 02142, USA
| | - Donglu Zhang
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., South San Francisco, CA, 94080, USA
| | - S Cyrus Khojasteh
- Department of Drug Metabolism and Pharmacokinetics, Genentech, Inc., 1 DNA Way, MS412a, South San Francisco, CA, 94080, USA
| |
Collapse
|
15
|
Adverse Drug Reactions in Relation to Clozapine Plasma Levels: A Systematic Review. Pharmaceuticals (Basel) 2022; 15:ph15070817. [PMID: 35890117 PMCID: PMC9317288 DOI: 10.3390/ph15070817] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 11/16/2022] Open
Abstract
Clozapine is the gold standard for treatment-resistant schizophrenia. Serious and even life-threatening adverse effects, mostly granulocytopenia, myocarditis, and constipation, are of great clinical concern and constitute a barrier to prescribing clozapine, thus depriving many eligible patients of a lifesaving treatment option. Interestingly, clozapine presents variable pharmacokinetics affected by numerous parameters, leading to significant inter- and intra-individual variation. Therefore, therapeutic drug monitoring of plasma clozapine levels confers a significant benefit in everyday clinical practice by increasing the confidence of the prescribing doctor to the drug and the adherence of the patient to the treatment, mainly by ensuring effective treatment and limited dose-related side effects. In the present systematic review, we aimed at identifying how a full range of adverse effects relates to plasma clozapine levels, using the Jadad grading system for assessing the quality of the available clinical evidence. Our findings indicate that EEG slowing, obsessive-compulsive symptoms, heart rate variability, hyperinsulinemia, metabolic syndrome, and constipation correlate to plasma clozapine levels, whereas QTc, myocarditis, sudden death, leucopenia, neutropenia, sialorrhea, are rather unrelated. Rapid dose escalation at the initiation of treatment might contribute to the emergence of myocarditis, or leucopenia. Strategies for managing adverse effects are different in these conditions and are discussed accordingly.
Collapse
|
16
|
Metabolite Profiling of Clozapine in Patients Switching Versus Maintaining Treatment: A Retrospective Pilot Study. J Clin Psychopharmacol 2022; 42:470-474. [PMID: 35916581 PMCID: PMC9426748 DOI: 10.1097/jcp.0000000000001585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE/BACKGROUND Pharmacokinetics may be of relevance for the risk of clozapine discontinuation. We compared metabolite profiles, accounting for smoking habits, in patients switching versus maintaining clozapine treatment at therapeutic concentrations. METHODS/PROCEDURES Adult patients with clozapine serum levels above 1070 nmol/L (350 ng/mL) were retrospectively included from a Norwegian therapeutic drug monitoring service during 2018-2020. Inclusion criteria were (1) known smoking habits, (2) blood sample drawn within 10 to 30 hours after last clozapine intake, and (3) detectable levels of N -desmethylclozapine, clozapine -N -oxide, clozapine-5 N -glucuronide, or clozapine- N + - glucuronide. Patients comedicated with cytochrome P450 enzyme inducers, inhibitors, or valproic acid were excluded. The high-resolution mass spectrometry assay enabled detection of 21 clozapine metabolites. Metabolite profiles were compared between patients switching treatment (switchers), measured as clozapine being replaced by another antipsychotic drug in blood samples, versus maintaining clozapine treatment (nonswitchers) during the study period. FINDINGS/RESULTS Of the 84 patients fulfilling the study criteria, 7 patients (8.3%) were identified as clozapine switchers. After correcting for smoking habits, the clozapine-5 N -glucuronide/clozapine ratio was 69% lower ( P < 0.001), while the clozapine- N + -glucuronide/clozapine-5 N -glucuronide ratio was 143% higher ( P = 0.026), respectively, in switchers versus nonswitchers. The other metabolite ratios did not significantly differ between switchers and nonswitchers. IMPLICATIONS/CONCLUSIONS The present study found a significantly reduced 5 N -glucuronidation phenotype in patients switching from clozapine at therapeutic serum concentrations (>1070 nmol/L) to other antipsychotic drugs. This may indicate that glucuronidation, as a potential detoxification mechanism, is related to clozapine tolerability. However, the causality of this observation needs to be investigated in future studies with larger patient populations.
Collapse
|
17
|
Abstract
BACKGROUND Valproic acid (VPA) is frequently used with clozapine (CLZ) as mood stabilizer and/or seizure prophylaxis. Valproic acid is known to reduce N-desmethylclozapine (N-DMC) but not CLZ levels. This leads to the hypothesis that VPA induces the CLZ metabolism via non-N-desmethylation pathways. Therefore, we aimed to investigate the effect of concurrent VPA use on the serum concentrations of a spectrum of CLZ metabolites in patients, adjusting for smoking. METHODS In total, 288 patients with an overall number of 737 serum concentration measurements of CLZ and metabolites concurrently using VPA (cases, n = 22) or no interacting drugs (controls, n = 266) were included from a routine therapeutic drug monitoring service. Linear mixed model analyses were performed to compare the dose-adjusted concentrations (C/D) of CLZ, N-DMC, CLZ 5N/N+-glucuronides, and metabolite-to-parent ratios in cases versus controls. RESULTS After adjusting for covariates, the N-DMC (-40%, P < 0.001) and N+-glucuronide C/Ds (-78%, P < 0.001) were reduced in cases versus controls, while the CLZ C/D was unchanged (P > 0.7). In contrast, the 5N-glucuronide C/D (+250%, P < 0.001) and 5N-glucuronide-to-CLZ ratios (+120%, P = 0.01) were increased in cases versus controls. CONCLUSIONS Our findings show that complex changes in CLZ metabolism underly the pharmacokinetic interaction with VPA. The lower levels of N-DMC seem to be caused by VPA-mediated induction of CLZ 5N-glucuronide formation, subsequently leading to reduced substrate availability for N-desmethylation. Whether the changes in CLZ metabolism caused by VPA affects the clinical outcome warrants further investigation.
Collapse
|
18
|
Sernoskie SC, Jee A, Uetrecht JP. The Emerging Role of the Innate Immune Response in Idiosyncratic Drug Reactions. Pharmacol Rev 2021; 73:861-896. [PMID: 34016669 DOI: 10.1124/pharmrev.120.000090] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Idiosyncratic drug reactions (IDRs) range from relatively common, mild reactions to rarer, potentially life-threatening adverse effects that pose significant risks to both human health and successful drug discovery. Most frequently, IDRs target the liver, skin, and blood or bone marrow. Clinical data indicate that most IDRs are mediated by an adaptive immune response against drug-modified proteins, formed when chemically reactive species of a drug bind to self-proteins, making them appear foreign to the immune system. Although much emphasis has been placed on characterizing the clinical presentation of IDRs and noting implicated drugs, limited research has focused on the mechanisms preceding the manifestations of these severe responses. Therefore, we propose that to address the knowledge gap between drug administration and onset of a severe IDR, more research is required to understand IDR-initiating mechanisms; namely, the role of the innate immune response. In this review, we outline the immune processes involved from neoantigen formation to the result of the formation of the immunologic synapse and suggest that this framework be applied to IDR research. Using four drugs associated with severe IDRs as examples (amoxicillin, amodiaquine, clozapine, and nevirapine), we also summarize clinical and animal model data that are supportive of an early innate immune response. Finally, we discuss how understanding the early steps in innate immune activation in the development of an adaptive IDR will be fundamental in risk assessment during drug development. SIGNIFICANCE STATEMENT: Although there is some understanding that certain adaptive immune mechanisms are involved in the development of idiosyncratic drug reactions, the early phase of these immune responses remains largely uncharacterized. The presented framework refocuses the investigation of IDR pathogenesis from severe clinical manifestations to the initiating innate immune mechanisms that, in contrast, may be quite mild or clinically silent. A comprehensive understanding of these early influences on IDR onset is crucial for accurate risk prediction, IDR prevention, and therapeutic intervention.
Collapse
Affiliation(s)
- Samantha Christine Sernoskie
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy (S.C.S., J.P.U.), and Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada (A.J., J.P.U.)
| | - Alison Jee
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy (S.C.S., J.P.U.), and Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada (A.J., J.P.U.)
| | - Jack Paul Uetrecht
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy (S.C.S., J.P.U.), and Department of Pharmacology and Toxicology, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada (A.J., J.P.U.)
| |
Collapse
|
19
|
Foster DJ, Bryant ZK, Conn PJ. Targeting muscarinic receptors to treat schizophrenia. Behav Brain Res 2021; 405:113201. [PMID: 33647377 PMCID: PMC8006961 DOI: 10.1016/j.bbr.2021.113201] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 02/02/2021] [Accepted: 02/18/2021] [Indexed: 11/23/2022]
Abstract
Schizophrenia is a severe neuropsychiatric disorder characterized by a diverse range of symptoms that can have profound impacts on the lives of patients. Currently available antipsychotics target dopamine receptors, and while they are useful for ameliorating the positive symptoms of the disorder, this approach often does not significantly improve negative and cognitive symptoms. Excitingly, preclinical and clinical research suggests that targeting specific muscarinic acetylcholine receptor subtypes could provide more comprehensive symptomatic relief with the potential to ameliorate numerous symptom domains. Mechanistic studies reveal that M1, M4, and M5 receptor subtypes can modulate the specific brain circuits and physiology that are disrupted in schizophrenia and are thought to underlie positive, negative, and cognitive symptoms. Novel therapeutic strategies for targeting these receptors are now advancing in clinical and preclinical development and expand upon the promise of these new treatment strategies to potentially provide more comprehensive relief than currently available antipsychotics.
Collapse
Affiliation(s)
- Daniel J Foster
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, 37232, United States
| | - Zoey K Bryant
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, 37232, United States
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, United States; Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, 37232, United States.
| |
Collapse
|
20
|
Thymoquinone reduces mitochondrial damage and death of cardiomyocytes induced by clozapine. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2021; 394:1675-1684. [PMID: 33937934 DOI: 10.1007/s00210-021-02095-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/20/2021] [Indexed: 10/21/2022]
Abstract
The generation of a reactive nitrenium ion by microsomal/mitochondrial cytochrome P450 (CYPs) from clozapine (CLZ) has been suggested as the main cause of cardiotoxicity by this drug. Previous studies indicated that thymoquinone (TQ) as an active constituent of Nigella sativa has pharmacological effects such as antioxidant, reactive oxygen species (ROS) scavenger, and inhibitory effect on CYPs enzymes. Therefore, we hypothesized that TQ with these pharmacological effects can reduce CLZ-induced toxicity in isolated cardiomyocytes and mitochondria. Rat left ventricular cardiomyocytes and mitochondria were isolated by collagenase perfusion and differential centrifugation respectively. Then, isolated cardiomyocytes and mitochondria were pretreated with different concentrations of TQ (1, 5, and 10 μmol/l) for 30 min and then followed by exposure to CLZ (50 μmol/l) for 6 h. After 6 h of incubation, using biochemical evaluations and flow cytometric analysis, the parameters of cellular toxicity including cytotoxicity, the level of oxidized/reduced glutathione (GSH/GSSG), malondialdehyde (MDA), reactive oxygen species (ROS) formation, lysosomal membrane integrity, mitochondria membrane potential (ΔΨm) collapse, and mitochondrial toxicity including succinate dehydrogenase (SDH) activity and mitochondrial swelling were analyzed. We observed a significant toxicity in isolated cardiomyocytes and mitochondria after exposure with CLZ which was related to ROS formation, oxidative stress, GSH depletion, lysosomal and mitochondrial damages, and mitochondrial dysfunction and swelling, while TQ pretreatment reverted the above toxic effect of CLZ on isolated cardiomyocytes and mitochondria. Our results indicate that TQ prevents and reverses CLZ-induced cytotoxicity and mitochondrial damages in isolated cardiomyocytes and mitochondria, providing an experimental basis for clinical treatment on CLZ-induced cardiotoxicity.
Collapse
|
21
|
Willcocks IR, Legge SE, Nalmpanti M, Mazzeo L, King A, Jansen J, Helthuis M, Owen MJ, O’Donovan MC, Walters JTR, Pardiñas AF. Clozapine Metabolism is Associated With Absolute Neutrophil Count in Individuals With Treatment-Resistant Schizophrenia. Front Pharmacol 2021; 12:658734. [PMID: 33959025 PMCID: PMC8094024 DOI: 10.3389/fphar.2021.658734] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/17/2021] [Indexed: 11/13/2022] Open
Abstract
Up to one-third of those with schizophrenia fail to respond to standard antipsychotics and are considered to have treatment-resistant schizophrenia, a condition for which clozapine is the only evidence-based medication. While up to 60% of treated individuals obtain therapeutic benefits from clozapine, it is currently underprescribed worldwide, partly because of concerns related to its broad adverse effect profile. In particular, the potential effects of clozapine on the immune system have gained relevance after a recent study showed that drug plasma concentrations were inversely correlated with neutrophil counts in individuals routinely undergoing treatment. Seeking to investigate this relationship in more detail, we extracted metabolic, immune, and genetic data from a UK cohort of long-term clozapine users linked to a clozapine monitoring service, CLOZUK2 (N = 208). Whilst a correlation analysis was compatible with the original results, a multiple linear regression accounting for dose and other confounding factors additionally allowed us to estimate the decrease in absolute neutrophil counts to approximately 141 cells/mm3 for every 0.1 mg/L increase in clozapine concentration. However, this association was attenuated after controlling for the metabolic ratio between clozapine and its main metabolite, norclozapine, which was itself negatively associated with neutrophil concentrations. Further analyses revealed that these relationships are likely moderated by genetic factors, as three pharmacogenomic SNPs previously associated to norclozapine plasma concentrations and the metabolic ratio (rs61750900, rs2011425 and rs1126545) were shown to be independently associated with a variation in neutrophil counts of about 400 cells/mm3 per effect allele. Such results are compatible with an effect of norclozapine, but not necessarily clozapine, on immune cell counts, and highlight the need for further investigations into the potential role of genetic determinants of clozapine pharmacokinetics in the occurrence of adverse effects during treatment.
Collapse
Affiliation(s)
- Isabella R. Willcocks
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Sophie E. Legge
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Mariana Nalmpanti
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Lucy Mazzeo
- Hafan y Coed Mental Health Unit, University Hospital of Llandough, Cardiff, United Kingdom
| | - Adrian King
- Magna Laboratories Ltd., Ross-on-Wye, United Kingdom
| | | | | | - Michael J. Owen
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Michael C. O’Donovan
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - James T. R. Walters
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Antonio F. Pardiñas
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, United Kingdom
| |
Collapse
|
22
|
Todorović Vukotić N, Đorđević J, Pejić S, Đorđević N, Pajović SB. Antidepressants- and antipsychotics-induced hepatotoxicity. Arch Toxicol 2021; 95:767-789. [PMID: 33398419 PMCID: PMC7781826 DOI: 10.1007/s00204-020-02963-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/26/2020] [Indexed: 02/06/2023]
Abstract
Drug-induced liver injury (DILI) is a serious health burden. It has diverse clinical presentations that can escalate to acute liver failure. The worldwide increase in the use of psychotropic drugs, their long-term use on a daily basis, common comorbidities of psychiatric and metabolic disorders, and polypharmacy in psychiatric patients increase the incidence of psychotropics-induced DILI. During the last 2 decades, hepatotoxicity of various antidepressants (ADs) and antipsychotics (APs) received much attention. Comprehensive review and discussion of accumulated literature data concerning this issue are performed in this study, as hepatotoxic effects of most commonly prescribed ADs and APs are classified, described, and discussed. The review focuses on ADs and APs characterized by the risk of causing liver damage and highlights the ones found to cause life-threatening or severe DILI cases. In parallel, an overview of hepatic oxidative stress, inflammation, and steatosis underlying DILI is provided, followed by extensive review and discussion of the pathophysiology of AD- and AP-induced DILI revealed in case reports, and animal and in vitro studies. The consequences of some ADs and APs ability to affect drug-metabolizing enzymes and therefore provoke drug–drug interactions are also addressed. Continuous collecting of data on drugs, mechanisms, and risk factors for DILI, as well as critical data reviewing, is crucial for easier DILI diagnosis and more efficient risk assessment of AD- and AP-induced DILI. Higher awareness of ADs and APs hepatotoxicity is the prerequisite for their safe use and optimal dosing.
Collapse
Affiliation(s)
- Nevena Todorović Vukotić
- Department of Molecular Biology and Endocrinology, "Vinča" Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 12-14 Mike Petrovića Alasa, P.O. Box 522-090, 11000, Belgrade, Serbia.
| | - Jelena Đorđević
- Institute of Physiology and Biochemistry "Ivan Đaja", Faculty of Biology, University of Belgrade, 16 Studentski Trg, 11000, Belgrade, Serbia
| | - Snežana Pejić
- Department of Molecular Biology and Endocrinology, "Vinča" Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 12-14 Mike Petrovića Alasa, P.O. Box 522-090, 11000, Belgrade, Serbia
| | - Neda Đorđević
- Department of Molecular Biology and Endocrinology, "Vinča" Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 12-14 Mike Petrovića Alasa, P.O. Box 522-090, 11000, Belgrade, Serbia
| | - Snežana B Pajović
- Department of Molecular Biology and Endocrinology, "Vinča" Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, 12-14 Mike Petrovića Alasa, P.O. Box 522-090, 11000, Belgrade, Serbia.,Faculty of Medicine, University of Niš, 81 Blvd. Dr. Zorana Đinđića, 18000, Niš, Serbia
| |
Collapse
|
23
|
Absolute and Dose-Adjusted Serum Concentrations of Clozapine in Patients Switching vs. Maintaining Treatment: An Observational Study of 1979 Patients. CNS Drugs 2021; 35:999-1008. [PMID: 34417726 PMCID: PMC8408068 DOI: 10.1007/s40263-021-00847-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/15/2021] [Indexed: 11/05/2022]
Abstract
BACKGROUND Clozapine is an effective drug for the management of schizophrenia that has not responded to other agents, but some patients experience insufficient or adverse effects and discontinue treatment. OBJECTIVE We investigated a potential association between clozapine serum concentrations and switching to other antipsychotics in a large real-world patient population from a therapeutic drug monitoring service. METHODS Absolute and dose-adjusted serum concentrations (concentration-to-dose ratios [C/D ratios]) of clozapine during dosing between 100 and 1000 mg/day were measured in 1979 Norwegian patients during the period 2005-2019. These variables were compared in patients switching to other antipsychotic drugs versus maintaining clozapine treatment using linear mixed models. Smoking habits were known for 49% of the patients. To prevent potential nonadherence affecting clozapine switching, only patients with serum concentrations above 50% of the lower reference range were included. RESULTS In total, 190 patients (9.6%) switched from clozapine to another antipsychotic drug during the study period, whereas the remaining patients were not detected as switchers and were interpreted as maintaining treatment. Patients switching treatment had 23.5% lower absolute concentrations (954 vs. 1245 nmol/L; p < 0.001) and 15.7% lower daily doses (305 vs. 362 mg/day; p < 0.001) of clozapine than did nonswitchers, making the clozapine C/D ratio 9.7% lower in switchers than in nonswitchers after correcting for smoking habits (2.80 vs. 3.10 nmol/L/mg/day; p = 0.032). CONCLUSIONS The present study suggests that decreased absolute and dose-adjusted serum concentrations of clozapine were associated with clozapine discontinuation. The significantly reduced clozapine concentrations regardless of prescribed dose in switchers versus nonswitchers may indicate a pharmacokinetic mechanism underlying the risk of clozapine discontinuation.
Collapse
|
24
|
Arzuk E, Karakuş F, Orhan H. Bioactivation of clozapine by mitochondria of the murine heart: Possible cause of cardiotoxicity. Toxicology 2020; 447:152628. [PMID: 33166605 DOI: 10.1016/j.tox.2020.152628] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/26/2020] [Accepted: 11/03/2020] [Indexed: 01/11/2023]
Abstract
The mechanism of clozapine-associated cardiotoxicity has not been elucidated. The formation of a reactive nitrenium ion from the drug has been suggested as the cause, however, the reason why the heart is a target remains unknown. The heart is one of the most perfused organs; therefore, it contains a large number of mitochondria per cell; these organelles are responsible for both oxygen metabolism and energy production due to high energy expenditure. Given that mitochondria play critical roles in cellular homeostasis and maintenance, this study tested the hypothesis that cardiac mitochondria are both a target and initiator of clozapine-induced cardiotoxicity through activating the drug. We investigated whether murine heart receives a relatively high amount of systemically administered drug (20 mg/kg, i.p., Wistar albino rats) and whether cardiac mice (Swiss albino) and rat (Wistar albino) mitochondria locally activate clozapine (100 μM) to a reactive metabolite. We observed a relatively large distribution of clozapine to heart tissue as well as the formation of reactive metabolites by cardiac mitochondria in situ. Mitochondrial cytochrome P450 enzymes (CYP) in cardiac tissue responsible for biotransformation of clozapine were also characterized. CYP3A4 has been found to be the major enzyme catalyzes CLZ bioactivation, while CYP1A largely and CYP3A4 partially catalyzes the formation of stable metabolites of CLZ. At 100 μM concentration, clozapine caused a significant decline in mitochondrial oxygen consumption rate in vitro as much as positive control (antimycin A), while it did not induce mitochondrial permeability transition pore opening. These data provide an explanation as to why the heart is a target for clozapine adverse effects.
Collapse
Affiliation(s)
- Ege Arzuk
- Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Ege University, 35040 Bornova-İzmir, Turkey
| | - Fuat Karakuş
- Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Ege University, 35040 Bornova-İzmir, Turkey
| | - Hilmi Orhan
- Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Ege University, 35040 Bornova-İzmir, Turkey.
| |
Collapse
|
25
|
Ogese MO, Lister A, Jenkins RE, Meng X, Alfirevic A, Douglas L, Mcloughlin R, Silva E, Park BK, Pirmohamed M, Naisbitt DJ. Characterization of Clozapine-Responsive Human T Cells. THE JOURNAL OF IMMUNOLOGY 2020; 205:2375-2390. [PMID: 32989092 DOI: 10.4049/jimmunol.2000646] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/27/2020] [Indexed: 01/02/2023]
Abstract
Use of the atypical antipsychotic clozapine is associated with life-threatening agranulocytosis. The delayed onset and the association with HLA variants are characteristic of an immunological mechanism. The objective of this study was to generate clozapine-specific T cell clones (TCC) and characterize pathways of T cell activation and cross-reactivity with clozapine metabolites and olanzapine. TCC were established and characterized by culturing PBMCs from healthy donors and patients with a history of clozapine-induced agranulocytosis. Modeling was used to explore the drug-HLA binding interaction. Global TCC protein changes were profiled by mass spectrometry. Six well-growing clozapine-responsive CD4+ and CD8+ TCC were used for experiments; activation of TCC required APC, with clozapine interacting directly at therapeutic concentrations with several HLA-DR molecules. TCC were also activated with N-desmethylclozapine and olanzapine at supratherapeutic concentrations. Marked changes in TCC protein expression profiles were observed when clozapine treatment was compared with olanzapine and the medium control. Docking of the compounds into the HLA-DRB1*15:01 and HLA-DRB1*04:01 binding clefts revealed that clozapine and olanzapine bind in a similar conformation to the P4-P6 peptide binding pockets, whereas clozapine N-oxide, which did not activate the TCC, bound in a different conformation. TCC secreted Th1, Th2, and Th22 cytokines and effector molecules and expressed TCR Vβ 5.1, 16, 20, and 22 as well as chemokine receptors CXCR3, CCR6, CCR4, and CCR9. Collectively, these data show that clozapine interacts at therapeutic concentrations with HLA-DR molecules and activates human CD4+ T cells. Olanzapine only activates TCC at supratherapeutic concentrations.
Collapse
Affiliation(s)
- Monday O Ogese
- Medical Research Council Centre for Drug Safety Science, Department Molecular and Clinical Pharmacology, University of Liverpool, Liverpool L69 3GE, United Kingdom
| | - Adam Lister
- Medical Research Council Centre for Drug Safety Science, Department Molecular and Clinical Pharmacology, University of Liverpool, Liverpool L69 3GE, United Kingdom
| | - Rosalind E Jenkins
- Medical Research Council Centre for Drug Safety Science, Department Molecular and Clinical Pharmacology, University of Liverpool, Liverpool L69 3GE, United Kingdom
| | - Xiaoli Meng
- Medical Research Council Centre for Drug Safety Science, Department Molecular and Clinical Pharmacology, University of Liverpool, Liverpool L69 3GE, United Kingdom
| | - Ana Alfirevic
- Medical Research Council Centre for Drug Safety Science, Department Molecular and Clinical Pharmacology, University of Liverpool, Liverpool L69 3GE, United Kingdom
| | - Lisa Douglas
- Cheshire and Wirral Partnership National Health Service Foundation Trust, Chester CH2 1BQ, United Kingdom; and
| | - Rachel Mcloughlin
- Cheshire and Wirral Partnership National Health Service Foundation Trust, Chester CH2 1BQ, United Kingdom; and
| | - Edward Silva
- Mersey Care National Health Service Foundation Trust, Rathbone Low Secure Unit, Rathbone Hospital, Liverpool L13 4AW, United Kingdom
| | - B Kevin Park
- Medical Research Council Centre for Drug Safety Science, Department Molecular and Clinical Pharmacology, University of Liverpool, Liverpool L69 3GE, United Kingdom
| | - Munir Pirmohamed
- Medical Research Council Centre for Drug Safety Science, Department Molecular and Clinical Pharmacology, University of Liverpool, Liverpool L69 3GE, United Kingdom
| | - Dean J Naisbitt
- Medical Research Council Centre for Drug Safety Science, Department Molecular and Clinical Pharmacology, University of Liverpool, Liverpool L69 3GE, United Kingdom;
| |
Collapse
|
26
|
Rahman H, Haque SM, Siddiqui MR. A Comprehensive Review on Importance and Quantitation of Atypical Antipsychotic Drugs and their Active Metabolites in Commercial Dosage Forms. CURR PHARM ANAL 2020. [DOI: 10.2174/1573412915666190328214323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:
Schizophrenia is a severe mental illness that affects more than twenty-one
million people throughout the world. Schizophrenia also causes early death. Schizophrenia and other
related psychotic ailments are controlled by the prescription of antipsychotic drugs, which act by blocking
certain chemical receptors in the brain and thus relieves the symptoms of psychotic disorder. These
drugs are present in the different dosage forms in the market and provided in a certain amount as per the
need of the patients.
Objective:
Since such medications treat mental disorders, it is very important to have a perfect and accurate
dose so that the risk factor is not affected by a higher or lower dose, which is not sufficient for
the treatment. For accurate assay of these kinds of drugs, different analytical methods were developed
ranging from older spectrophotometric techniques to latest hyphenated methods.
Results:
The current review highlights the role of different analytical techniques that were employed in
the determination and identification of antipsychotic drugs and their metabolites. Techniques such as
spectrophotometry, fluorimetry, liquid chromatography, liquid chromatography-mass spectrometry, gas
chromatography, and gas chromatography-mass spectrometry employed in the method development of
such antipsychotic drugs were reported in the review. Different metabolites, identified using the hyphenated
techniques, were also mentioned in the review. The synthesis pathways of few of the metabolites
were mentioned.
Conclusion:
The review summarizes the analyses of different antipsychotic drugs and their metabolites.
A brief introduction of illnesses and their symptoms and possible medications were highlighted. Synthesis
pathways of the associated metabolites were also mentioned.
Collapse
Affiliation(s)
- Habibur Rahman
- Department of General Studies, Jubail Industrial College, P.O. Box No. 10099, Zip Code–31961, Jubail, Saudi Arabia
| | - S.K. Manirul Haque
- Department of Chemical & Process Engineering Technology, Jubail Industrial College, P.O. Box No 10099, Zip Code- 31961, Jubail, Saudi Arabia
| | - Masoom Raza Siddiqui
- Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| |
Collapse
|
27
|
Smith RL, O'Connell K, Athanasiu L, Djurovic S, Kringen MK, Andreassen OA, Molden E. Identification of a novel polymorphism associated with reduced clozapine concentration in schizophrenia patients-a genome-wide association study adjusting for smoking habits. Transl Psychiatry 2020; 10:198. [PMID: 32555152 PMCID: PMC7303159 DOI: 10.1038/s41398-020-00888-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 06/09/2020] [Accepted: 06/09/2020] [Indexed: 11/28/2022] Open
Abstract
Clozapine (CLZ) is the superior antipsychotic drug for treatment of schizophrenia, but exhibits an extensive interpatient pharmacokinetic variability. Here, we conducted a genome-wide association study (GWAS) of CLZ serum concentration adjusting for known smoking habits, which is a major nongenetic factor reducing CLZ levels. The study included 484 patients with 10,283 steady-state serum concentrations of CLZ and N-desmethylclozapine, prescribed dosing, co-medications and known smoking habits (n = 422; 9284 serum samples) from a therapeutic drug monitoring (TDM) service. The GWAS analyses were performed with and without smoking habits as covariate, where possible hits were assessed in relation to the target CLZ concentration range applied in the TDM service (300-2500 nmol/L). The smoking-independent analysis of N-desmethylclozapine serum concentration and the CLZ-to-N-desmethylclozapine ratio replicated the previously identified locus on chromosome 4. After adjusting for smoking habits in patients confirmed as 'smokers' (61%) or 'nonsmokers' (39%), a novel variant (rs28379954; minor T>C allele frequency 4.1%; 7.6% CT carriers in the population) within the gene encoding the nuclear factor 1 B-type (NFIB) was significantly associated with reduced CLZ serum concentration (p = 1.68 × 10-8, beta = -0.376; explained variance 7.63%). There was no significant association between rs28379954 and N-desmethylclozapine concentration in the GWAS analysis (p = 5.63 × 10-5). The fraction of CLZ TDM samples below 300 nmol/L was significantly higher in carriers vs. noncarriers of the rs28379954 minor C allele [12.0% (95% CI: 9.4-14.7) vs. 6.2% (95% CI: 5.7-6.8), p < 0.001]. We identified a novel variant in the NFIB gene associated with reduced CLZ levels and increased risk of subtherapeutic serum concentrations. This warrants testing of clinical relevance of screening for this gene variant, and also experimental studies to investigate the biological mechanisms of NFIB involvement in CLZ pharmacokinetics.
Collapse
Affiliation(s)
| | - Kevin O'Connell
- CoE NORMENT, Division of Mental Health and Addiction, Oslo University Hospital, and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Lavinia Athanasiu
- CoE NORMENT, Division of Mental Health and Addiction, Oslo University Hospital, and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Srdjan Djurovic
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
- NORMENT, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Marianne Kristiansen Kringen
- Center for Psychopharmacology, Diakonhjemmet Hospital, Oslo, Norway
- Department of Life Sciences and Health, Oslo Metropolitan University, Oslo, Norway
| | - Ole A Andreassen
- CoE NORMENT, Division of Mental Health and Addiction, Oslo University Hospital, and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Espen Molden
- Center for Psychopharmacology, Diakonhjemmet Hospital, Oslo, Norway.
- Department of Pharmacy, Section for Pharmacology and Pharmaceutical Biosciences, University of Oslo, Oslo, Norway.
| |
Collapse
|
28
|
Reduction in N-Desmethylclozapine Level Is Determined by Daily Dose But Not Serum Concentration of Valproic Acid-Indications of a Presystemic Interaction Mechanism. Ther Drug Monit 2020; 41:503-508. [PMID: 31259880 DOI: 10.1097/ftd.0000000000000619] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Valproic acid (VPA) is frequently used together with clozapine (CLZ) as mood-stabilizer or for the prevention of seizures in patients with psychotic disorders. VPA is known to reduce levels of the pharmacologically active CLZ-metabolite N-desmethylclozapine (N-DMC), but factors determining the degree of this interaction are unknown. Here, we investigated the relationship between VPA dose and serum concentration on N-DMC levels in a large patient population adjusting for sex, age, and smoking habits as covariates. METHODS A total of 763 patients with steady-state serum concentrations of CLZ and N-DMC concurrently using VPA (cases, n = 76) or no interacting drugs (controls, n = 687) were retrospectively included from a therapeutic drug monitoring service at Diakonhjemmet Hospital, Oslo, between March 2005 and December 2016. In addition to information about prescribed doses, age, sex, smoking habits, and use of other interacting drugs were obtained. The effects of VPA dose and serum concentration on dose-adjusted N-DMC levels were evaluated by univariate correlation and multivariate linear mixed-model analyses adjusting for covariates. RESULTS The dose-adjusted N-DMC levels were approximately 38% lower in VPA users (cases) versus nonusers (controls) (P < 0.001). Within the VPA cases, a negatively correlation between VPA dose and dose-adjusted N-DMC levels was observed with an estimated reduction of 1.42% per 100-mg VPA dose (P = 0.033) after adjusting for sex, age, and smoking. By contrast, there was no correlation between VPA serum concentration and dose-adjusted N-DMC levels (P = 0.873). CONCLUSIONS The study shows that VPA dose, not concentration, is of relevance for the degree of reduction in N-DMC level in clozapine-treated patients. Presystemic induction of UGT enzymes or efflux transporters might underlie the reduction in N-DMC level during concurrent use of VPA. Our findings indicate that a VPA daily dose of 1500 mg or higher provides a further 21% reduction in N-DMC concentration. This is likely a relevant change in the exposure of this active metabolite where low levels are associated with implications of CLZ therapy.
Collapse
|
29
|
Costa-Dookhan KA, Agarwal SM, Chintoh A, Tran VN, Stogios N, Ebdrup BH, Sockalingam S, Rajji TK, Remington GJ, Siskind D, Hahn MK. The clozapine to norclozapine ratio: a narrative review of the clinical utility to minimize metabolic risk and enhance clozapine efficacy. Expert Opin Drug Saf 2019; 19:43-57. [PMID: 31770500 DOI: 10.1080/14740338.2020.1698545] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Introduction: Clozapine remains the most effective antipsychotic for treatment-refractory schizophrenia. However, ~40% of the patients respond insufficiently to clozapine. Clozapine's effects, both beneficial and adverse, have been proposed to be partially attributable to its main metabolite, N-desmethylclozapine (NDMC). However, the relation of the clozapine to norclozapine ratio (CLZ:NDMC; optimally defined as ~2) to clinical response and metabolic outcomes is not clear.Areas covered: This narrative review comprehensively examines the clinical utility of the CLZ:NDMC ratio to reduce metabolic risk and increase treatment efficacy. The association of the CLZ:NDMC ratio with changes in psychopathology, cognitive functioning, and cardiometabolic burden will be explored, as well as adjunctive treatments and their effects.Expert opinion: The literature suggests a positive association between the CLZ:NDMC ratio and better cardiometabolic outcomes. Conversely, the CLZ:NDMC ratio appears inversely associated with better cognitive functioning but less consistently with other psychiatric domains. The CLZ:NDMC ratio may be useful for predicting and monitoring cardiometabolic adverse effects and optimizing potential cognitive benefits of clozapine. Future studies are required to replicate these findings, which if substantiated, would encourage examination of adjunctive treatments aiming to alter the CLZ:NDMC ratio to best meet the needs of the individual patient, thereby broadening clozapine's clinical utility.
Collapse
Affiliation(s)
- Kenya A Costa-Dookhan
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Sri Mahavir Agarwal
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Araba Chintoh
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Veronica N Tran
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Nicolette Stogios
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Bjørn H Ebdrup
- Centre for Neuropsychiatric Schizophrenia Research, CNSR & Centre for Clinical Intervention and Neuropsychiatric Schizophrenia Research, CINS, Mental Health Centre Glostrup, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sanjeev Sockalingam
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Tarek K Rajji
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Gary J Remington
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada
| | - Dan Siskind
- School of Medicine, University of Queensland, Brisbane, Australia.,Schizophrenia Department, Metro South Addiction and Mental Health Service, Brisbane, Australia
| | - Margaret K Hahn
- Schizophrenia Department, Centre for Addiction and Mental Health, Toronto, Canada.,Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Canada.,Department of Psychiatry, University of Toronto, Toronto, Canada.,Banting and Best Diabetes Centre, University of Toronto, Toronto, Canada
| |
Collapse
|
30
|
Lesche D, Mostafa S, Everall I, Pantelis C, Bousman CA. Impact of CYP1A2, CYP2C19, and CYP2D6 genotype- and phenoconversion-predicted enzyme activity on clozapine exposure and symptom severity. THE PHARMACOGENOMICS JOURNAL 2019; 20:192-201. [PMID: 31616047 DOI: 10.1038/s41397-019-0108-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 09/09/2019] [Accepted: 10/02/2019] [Indexed: 12/14/2022]
Abstract
Clozapine is an atypical antipsychotic metabolized by CYP1A2, CYP2D6, and CYP2C19 enzymes. Among 66 adult schizophrenia patients treated with clozapine-based combination therapies, we explored the impact of genotype-predicted CYP1A2, CYP2D6, and CYP2C19 activity on dose-adjusted clozapine concentrations and symptom severity, with and without correction for inhibitors and inducers of these enzymes. Uncorrected activity scores were not associated with dose-adjusted clozapine concentrations or symptom severity. CYP1A2 and CYP2D6 activity scores corrected for known inducers (i.e., smoking) and inhibitors (e.g., concomitant medications) were associated with dose-adjusted clozapine levels and in the case of CYP1A2, symptom severity. However, smoking status and certain inhibitors of clozapine metabolism (i.e., esomeprazole) explained significantly more variance in dose-adjusted clozapine levels relative to corrected activity scores. These findings highlight the clinical importance of nongenetic factors (smoking, concomitant medications) and suggest that the added utility of CYP1A2, CYP2D6, and CYP2C19 activity scores to guide clozapine dosing is currently limited.
Collapse
Affiliation(s)
- Dorothea Lesche
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne & Melbourne Health, Melbourne, VIC, Australia
| | - Sam Mostafa
- myDNA Life Australia Limited, South Yarra, VIC, Australia.,Centre for Medicine Use and Safety, Monash University, Parkville, VIC, Australia
| | - Ian Everall
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne & Melbourne Health, Melbourne, VIC, Australia.,Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia.,The Cooperative Research Centre (CRC) for Mental Health, VIC, Australia
| | - Christos Pantelis
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne & Melbourne Health, Melbourne, VIC, Australia.,Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia.,The Cooperative Research Centre (CRC) for Mental Health, VIC, Australia
| | - Chad A Bousman
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne & Melbourne Health, Melbourne, VIC, Australia. .,The Cooperative Research Centre (CRC) for Mental Health, VIC, Australia. .,Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada. .,Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada. .,Departments of Medical Genetics, Psychiatry, and Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada.
| |
Collapse
|
31
|
|
32
|
Filippova NV, Barylnik YB, Shuldyakov AA. The efficacy of remaxol as a hepatoprotective agent in long-term psychopharmacotherapy. Zh Nevrol Psikhiatr Im S S Korsakova 2019; 119:43-46. [DOI: 10.17116/jnevro201911901143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
33
|
Gilliland RA, Möller C, DeCaprio AP. LC-MS/MS based detection and characterization of covalent glutathione modifications formed by reactive drug of abuse metabolites. Xenobiotica 2018; 49:778-790. [PMID: 30070591 DOI: 10.1080/00498254.2018.1504256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Conjugation with the tripeptide glutathione (GSH) is a common mechanism of detoxification of many endogenous and exogenous compounds. This phenomenon typically occurs through the formation of a covalent bond between the nucleophilic free thiol moiety of GSH and an electrophilic site on the compound of interest. While GSH adducts have been identified for many licit drugs, there is a lack of information on the ability of drugs of abuse to adduct GSH. The present study utilized a metabolic assay with GSH as a nucleophilic trapping agent to bind reactive drug metabolites formed in situ. Extracted ion MS spectra were collected via LC-QqQ-MS/MS for all potentially significant ions and examined for fragmentation common to GSH-containing compounds, followed by confirmation of adduction and structural characterization performed by LC-QTOF-MS/MS. In addition to the two positive controls, of the 14 drugs of abuse tested, 10 exhibited GSH adduction, with several forming multiple adducts, resulting in a total of 22 individual identified adducts. A number of these are previously unreported in the literature, including those for diazepam, naltrexone, oxycodone and Δ9-THC.
Collapse
Affiliation(s)
- R Allen Gilliland
- a Department of Chemistry & Biochemistry and International Forensic Research Institute , Florida International University , Miami , FL , USA
| | - Carolina Möller
- a Department of Chemistry & Biochemistry and International Forensic Research Institute , Florida International University , Miami , FL , USA
| | - Anthony P DeCaprio
- a Department of Chemistry & Biochemistry and International Forensic Research Institute , Florida International University , Miami , FL , USA
| |
Collapse
|
34
|
Gawlik M, Skibiński R. Simulation of phase I metabolism reactions of clozapine by HLM and photocatalytic methods with the use of UHPLC-ESI-MS/MS. Biomed Chromatogr 2018; 32:e4297. [PMID: 29799621 DOI: 10.1002/bmc.4297] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 05/08/2018] [Accepted: 05/14/2018] [Indexed: 01/14/2023]
Abstract
In this study the comparison of human liver microsomes in in vitro incubation as well as ZnO- and TiO2 -assisted photocatalytic degradation of clozapine as a mimicking method of phase I metabolism transformation was performed. Based on reversed-phase UHPLC separation and high-resolution MS/MS data, eight transformation products were identified and seven of them were found to be hepatic metabolites of the parent compound. The multivariate chemometric comparison of the obtained results shows ZnO-assisted photocatalysis to be a more suitable approach to phase I metabolism simulation. The photocatalytic experiments demonstrated that the disappearance of clozapine followed pseudo-zero order kinetics.
Collapse
Affiliation(s)
- Maciej Gawlik
- Department of Medicinal Chemistry, Medical University of Lublin, Lublin, Poland
| | - Robert Skibiński
- Department of Medicinal Chemistry, Medical University of Lublin, Lublin, Poland
| |
Collapse
|
35
|
Reinen J, Smit M, Wenker M. Evaluation of Strategies for the Assessment of Drug–Drug Interactions Involving Cytochrome P450 Enzymes. Eur J Drug Metab Pharmacokinet 2018; 43:737-750. [DOI: 10.1007/s13318-018-0485-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
36
|
|
37
|
Wang Z, Fang Y, Rock D, Ma J. Rapid screening and characterization of glutathione-trapped reactive metabolites using a polarity switch-based approach on a high-resolution quadrupole orbitrap mass spectrometer. Anal Bioanal Chem 2017; 410:1595-1606. [DOI: 10.1007/s00216-017-0814-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 11/30/2017] [Accepted: 12/06/2017] [Indexed: 12/31/2022]
|
38
|
Piatkov I, Caetano D, Assur Y, Lau SL, Coelho M, Jones T, Nguyen T, Boyages S, McLean M. CYP2C19*17 protects against metabolic complications of clozapine treatment. World J Biol Psychiatry 2017; 18:521-527. [PMID: 28664816 DOI: 10.1080/15622975.2017.1347712] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OBJECTIVES Clozapine (CZ) is the most effective drug for managing treatment-resistant schizophrenic disorders. Its use has been limited due to adverse effects, which include weight gain and new-onset diabetes, but the incidence of these varies between patients. METHODS We investigated 187 Clozapine Clinic patients (of whom 137 consented for genotyping) for the presence of CYP2C19*17 and its association with CZ and norclozapine (NCZ) levels, and clinical outcomes. RESULTS Thirty-nine percent of genotyped patients were carriers of the CYP2C 19*17 polymorphism. This group demonstrated significantly higher NCZ serum levels, and significantly lower fasting glucose (5.66 ± 1.19 vs 6.72 ± 3.01 mmol/l, P = 0.009) and Hb1Ac (35.36 ± 4.78 vs 49.40 ± 20.60 mmol/mol, P = 0.006) levels compared to non-carriers of this polymorphism. CZ-treated patients with CYP2C19*17/*17 had a significantly lower prevalence of diabetes as well as a higher likelihood of clinical improvement of their schizophrenia, compared to those without this polymorphism (P = 0.012 and P = 0.031, respectively). CONCLUSIONS Our data suggest that CYP2C19*17 ultra-rapid-metaboliser status is a protective factor against the development of diabetes during clozapine treatment, and increases the likelihood of improvement in schizophrenia. The role of NCZ in treatment response and side effects, including metabolic syndrome, warrants further pharmacogenetic, pharmacokinetic and pharmacodynamic studies.
Collapse
Affiliation(s)
- Irina Piatkov
- a Molecular Research Laboratory, Blacktown Clinical School and Research Centre , Blacktown Hospital, WSU/WSLHD , Blacktown , Australia
| | - Dorgival Caetano
- b Western Sydney University School of Medicine , Campbelltown , NSW , Australia.,c Blacktown Mental Health Service , Blacktown Hospital, WSLHD , Blacktown , Australia
| | - Yolinda Assur
- c Blacktown Mental Health Service , Blacktown Hospital, WSLHD , Blacktown , Australia
| | - Sue Lynn Lau
- b Western Sydney University School of Medicine , Campbelltown , NSW , Australia
| | - Micheline Coelho
- a Molecular Research Laboratory, Blacktown Clinical School and Research Centre , Blacktown Hospital, WSU/WSLHD , Blacktown , Australia
| | - Trudi Jones
- a Molecular Research Laboratory, Blacktown Clinical School and Research Centre , Blacktown Hospital, WSU/WSLHD , Blacktown , Australia
| | - Tristan Nguyen
- a Molecular Research Laboratory, Blacktown Clinical School and Research Centre , Blacktown Hospital, WSU/WSLHD , Blacktown , Australia
| | - Steven Boyages
- b Western Sydney University School of Medicine , Campbelltown , NSW , Australia
| | - Mark McLean
- b Western Sydney University School of Medicine , Campbelltown , NSW , Australia
| |
Collapse
|
39
|
Akamine Y, Sugawara-Kikuchi Y, Uno T, Shimizu T, Miura M. Quantification of the steady-state plasma concentrations of clozapine and N-desmethylclozapine in Japanese patients with schizophrenia using a novel HPLC method and the effects of CYPs and ABC transporters polymorphisms. Ann Clin Biochem 2017; 54:677-685. [PMID: 27932669 DOI: 10.1177/0004563216686377] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Background This study developed a novel high-performance liquid chromatography (HPLC) method for the simultaneous quantification of clozapine and its active metabolite, N-desmethylclozapine, in human plasma and investigated the effects of various factors, including genetic polymorphisms in cytochrome P450 (CYP) 2D6, CYP3A5, ABCB1 and ABCG2, on the steady-state plasma trough concentrations (C0) of clozapine and N-desmethylclozapine in Japanese patients with schizophrenia. Methods Forty-five patients had been receiving fixed doses of clozapine for at least four weeks. The CYP2D6 ( CYP2D6*2, CYP2D6*5, CYP2D6*10), CYP3A5 ( CYP3A5*3), ABCB1 (1236C > T, 2677G > T/A, 3435C > T) and ABCG2 (421 C > A) genotypes were identified by polymerase chain reaction. Results The within- and between-day coefficients of variation (CV) were less than 11.0%, and accuracy was within 9.0% over the linear range from 10 to 2500 ng/mL for both analytes, and their LOQs were each 10 ng/mL. The median C0/dose (C0/D) ratios of clozapine were significantly higher in patients with the ABCG2 421 A allele than in those with the 421 C/C genotype ( P = 0.010). However, there were no significant differences in C0/D ratios of clozapine and N-desmethylclozapine among ABCB1, CYP2D6 or CYP3A5 genotypes. In multiple regression analysis, including polymorphisms, age, body weight and biochemical data of patients, the ABCG2 polymorphism alone was correlated with the C0/D ratios of clozapine ( R2 = 0.139, P = 0.016). Conclusions Among the various CYPs and drug transporters, BCRP appeared to most strongly influence clozapine exposure. Knowledge of the patient's ABCG2 421 C > A genotype before initiating therapy may be useful when making dosing decisions aimed at achieving optimal clozapine exposure.
Collapse
Affiliation(s)
- Yumiko Akamine
- 1 Department of Pharmacy, Akita University Hospital, Akita, Japan
| | - Yuka Sugawara-Kikuchi
- 2 Department of Neuropsychiatry, Akita University Graduate School of Medicine, Akita, Japan
| | - Tsukasa Uno
- 3 Department of Pharmacy, Zikeikai-Aoimori Hospital, Aomori, Japan
| | - Tetsuo Shimizu
- 2 Department of Neuropsychiatry, Akita University Graduate School of Medicine, Akita, Japan
| | - Masatomo Miura
- 1 Department of Pharmacy, Akita University Hospital, Akita, Japan
| |
Collapse
|
40
|
den Braver MW, Vermeulen NPE, Commandeur JNM. Generic method for the absolute quantification of glutathione S-conjugates: Application to the conjugates of acetaminophen, clozapine and diclofenac. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1046:185-194. [PMID: 28189104 DOI: 10.1016/j.jchromb.2017.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/02/2017] [Accepted: 02/04/2017] [Indexed: 10/20/2022]
Abstract
Modification of cellular macromolecules by reactive drug metabolites is considered to play an important role in the initiation of tissue injury by many drugs. Detection and identification of reactive intermediates is often performed by analyzing the conjugates formed after trapping by glutathione (GSH). Although sensitivity of modern mass spectrometrical methods is extremely high, absolute quantification of GSH-conjugates is critically dependent on the availability of authentic references. Although 1H NMR is currently the method of choice for quantification of metabolites formed biosynthetically, its intrinsically low sensitivity can be a limiting factor in quantification of GSH-conjugates which generally are formed at low levels. In the present study, a simple but sensitive and generic method for absolute quantification of GSH-conjugates is presented. The method is based on quantitative alkaline hydrolysis of GSH-conjugates and subsequent quantification of glutamic acid and glycine by HPLC after precolumn derivatization with o-phthaldialdehyde/N-acetylcysteine (OPA/NAC). Because of the lower stability of the glycine OPA/NAC-derivate, quantification of the glutamic acid OPA/NAC-derivate appeared most suitable for quantification of GSH-conjugates. The novel method was used to quantify the concentrations of GSH-conjugates of diclofenac, clozapine and acetaminophen and quantification was consistent with 1H NMR, but with a more than 100-fold lower detection limit for absolute quantification.
Collapse
Affiliation(s)
- Michiel W den Braver
- AIMMS-Division of Molecular Toxicology, Department of Chemistry and Pharmaceutical sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Nico P E Vermeulen
- AIMMS-Division of Molecular Toxicology, Department of Chemistry and Pharmaceutical sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands
| | - Jan N M Commandeur
- AIMMS-Division of Molecular Toxicology, Department of Chemistry and Pharmaceutical sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
| |
Collapse
|
41
|
An integrated approach for profiling oxidative metabolites and glutathione adducts using liquid chromatography coupled with ultraviolet detection and triple quadrupole-linear ion trap mass spectrometry. J Pharm Biomed Anal 2016; 129:482-491. [DOI: 10.1016/j.jpba.2016.07.048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/28/2016] [Accepted: 07/29/2016] [Indexed: 11/18/2022]
|
42
|
Hellman K, Aadal Nielsen P, Ek F, Olsson R. An ex Vivo Model for Evaluating Blood-Brain Barrier Permeability, Efflux, and Drug Metabolism. ACS Chem Neurosci 2016; 7:668-80. [PMID: 26930271 DOI: 10.1021/acschemneuro.6b00024] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The metabolism of drugs in the brain is difficult to study in most species because of enzymatic instability in vitro and interference from peripheral metabolism in vivo. A locust ex vivo model that combines brain barrier penetration, efflux, metabolism, and analysis of the unbound fraction in intact brains was evaluated using known drugs. Clozapine was analyzed, and its major metabolites, clozapine N-oxide (CNO) and N-desmethylclozapine (NDMC), were identified and quantified. The back-transformation of CNO into clozapine observed in humans was also observed in locusts. In addition, risperidone, citalopram, fluoxetine, and haloperidol were studied, and one preselected metabolite for each drug was analyzed, identified, and quantified. Metabolite identification studies of clozapine and midazolam showed that the locust brain was highly metabolically active, and 18 and 14 metabolites, respectively, were identified. The unbound drug fraction of clozapine, NDMC, carbamazepine, and risperidone was analyzed. In addition, coadministration of drugs with verapamil or fluvoxamine was performed to evaluate drug-drug interactions in all setups. All findings correlated well with the data in the literature for mammals except for the stated fact that CNO is a highly blood-brain barrier permeant compound. Overall, the experiments indicated that invertebrates might be useful for screening of blood-brain barrier permeation, efflux, metabolism, and analysis of the unbound fraction of drugs in the brain in early drug discovery.
Collapse
Affiliation(s)
- Karin Hellman
- Chemical Biology & Therapeutics unit, Department of Experimental Medical Science, Lund University, Lund S-22184, Sweden
| | | | - Fredrik Ek
- Chemical Biology & Therapeutics unit, Department of Experimental Medical Science, Lund University, Lund S-22184, Sweden
| | - Roger Olsson
- Chemical Biology & Therapeutics unit, Department of Experimental Medical Science, Lund University, Lund S-22184, Sweden
| |
Collapse
|
43
|
Jiang L, Wu X, Wang S, Chen SH, Zhou H, Wilson B, Jin CY, Lu RB, Xie K, Wang Q, Hong JS. Clozapine metabolites protect dopaminergic neurons through inhibition of microglial NADPH oxidase. J Neuroinflammation 2016; 13:110. [PMID: 27184631 PMCID: PMC4869380 DOI: 10.1186/s12974-016-0573-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/06/2016] [Indexed: 01/02/2023] Open
Abstract
Background Clozapine, an atypical antipsychotic medication, has been effectively used to treat refractory schizophrenia. However, the clinical usage of clozapine is limited due to a high incidence of neutropenia or agranulocytosis. We previously reported that clozapine protected dopaminergic neurons through inhibition of microglial activation. The purpose of this study was to explore the neuroprotective effects of clozapine metabolites clozapine N-oxide (CNO) and N-desmethylclozapine (NDC), as well as their propensity to cause neutropenia. Methods The primary midbrain neuron-glia culture was applied to detect the neuroprotective and anti-inflammatory effect of clozapine and its metabolites in lipopolysaccharide (LPS) and MPP+-induced toxicity. And the subsequent mechanism was demonstrated by gp91phox mutant cell cultures as well as microgliosis cell lines. In vivo, to confirm the neuroprotective effect of clozapine and CNO, we measured the dopaminergic neuronal loss and rotarod motor deficits in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-generated mouse Parkinson’s disease (PD) model. The neutropenia or agranulocytosis of clozapine and its metabolites was illustrated by white blood cell count of the treated mice. Results We found that, in midbrain neuron-glia cultures, CNO and NDC were more potent than clozapine in protecting dopaminergic neurons against LPS and MPP+-induced toxicity. CNO and NDC-afforded neuroprotection was linked to inhibition of microglia-mediated neuroinflammation, as demonstrated by abolished neuroprotection in microglia-depleted cultures and their capacity of inhibiting LPS-induced release of proinflammatory factors from activated microglia. NADPH oxidase (NOX2) was subsequently recognized as the main target of CNO and NDC since genetic ablation of gp91phox, the catalytic subunit of NOX2, abolished their neuroprotective effects. CNO and NDC inhibited NOX2 activation through interfering with the membrane translocation of the NOX2 cytosolic subunit, p47phox. The neuroprotective effects of CNO were further verified in vivo as shown by attenuation of dopaminergic neurodegeneration, motor deficits, and reactive microgliosis in MPTP-generated mouse PD model. More importantly, unlike clozapine, CNO did not lower the white blood cell count. Conclusions Altogether, our results show that clozapine metabolites elicited neuroprotection through inactivation of microglia by inhibiting NOX2. The robust neuroprotective effects and lack of neutropenia suggest that clozapine metabolites may be promising candidates for potential therapy for neurodegenerative diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0573-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Lulu Jiang
- Neuropharmacology Section, Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA.,Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong, 250012, China
| | - Xuefei Wu
- Department of Physiology, Dalian Medical University, Dalian, Liaoning, 116044, China
| | - Shuo Wang
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong, 250012, China
| | - Shih-Heng Chen
- Neuropharmacology Section, Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Hui Zhou
- Department of Occupational and Environmental Health, School of Public Health, Peking University, Beijing, 100191, China
| | - Belinda Wilson
- Neuropharmacology Section, Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Chun-Yang Jin
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC, 27709, USA
| | - Ru-Band Lu
- Department of Psychiatry, Institute of Behavioral Medicine, Institute of Allied Health Sciences and Addiction Research Center, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 70101, Taiwan.,Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli, 35035, Taiwan
| | - Keqin Xie
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, Shandong, 250012, China.
| | - Qingshan Wang
- Department of Occupational and Environmental Health, School of Public Health, Dalian Medical University, Dalian, Liaoning, 116044, China.
| | - Jau-Shyong Hong
- Neuropharmacology Section, Laboratory of Neurobiology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| |
Collapse
|
44
|
Caetano D, Piatkov I. Ultrarapid clozapine metabolism and CYP2D6 gene duplication in a patient with schizophrenia. Per Med 2016; 13:113-117. [DOI: 10.2217/pme.15.56] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
An optimal clozapine serum level is required for both optimization of clinical response and minimization of troublesome or some of the life-threatening side effects. Serum levels can be influenced by comedication that can cause phenoconversion. When norclozapine/clozapine serum levels and ratios are consistently and significantly lower/higher than expected and there are no concomitant drugs that could account for these findings, further investigation of the genetic variants of CYP1A2, 2D6 and 3A4 are warranted.
Collapse
Affiliation(s)
- Dorgival Caetano
- Blacktown Mental Health Service, WSLHD, Blacktown, Australia
- Blacktown Clinical School and Research Centre, WSLHD, Blacktown, 2148, Australia
| | - Irina Piatkov
- Blacktown Clinical School and Research Centre, WSLHD, Blacktown, 2148, Australia
| |
Collapse
|
45
|
Caetano D, Piatkov I. Higher than expected clozapine serum level and clozapine/norclozapine ratio due to CYP450 gene polymorphisms. Per Med 2015; 12:555-558. [DOI: 10.2217/pme.15.33] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aims: We investigated a case of the unexpectedly high clozapine/norclozapine serum levels in a non-smoker, female patient. Method: The RFLP genotype method was used for the loss-of-function CYP450 gene polymorphisms detection. Results: The genotype revealed the presence of CYP2D6*41/*41, rs28371725, NM_000106.5:c.985+39G>A and CYP1A2*1/*1D rs35694136, NM_000761.4:c.-1635delT. Conclusion: An appropriate clozapine serum level is required for both optimization of clinical response and avoidance of troublesome, or even life-threatening side effects. Although not the only factor, genetic polymorphisms responsible for the metabolism of clozapine play an important role towards such goals. Pharmacogenetic tests can guide dose adjustment in order to obtain an optimum serum level, which can lead to a better therapeutic response and minimization of harmful side effects.
Collapse
Affiliation(s)
- Dorgival Caetano
- Blacktown Mental Health Service, WSLHD, Blacktown, NSW, 2148, Australia
- Blacktown Clinical School & Research Centre, WSLHD, Blacktown, NSW, 2148, Australia
| | - Irina Piatkov
- Blacktown Clinical School & Research Centre, WSLHD, Blacktown, NSW, 2148, Australia
| |
Collapse
|
46
|
Tseng PT, Chang YC, Chang CH, Wang HY, Cheng YS, Wu CK, Chen YW, Chung W. Atypical neuroleptic malignant syndrome in patients treated with aripiprazole and clozapine: a case-series study and short review. Int J Psychiatry Med 2015; 49:35-43. [PMID: 25838319 DOI: 10.2190/pm.49.1.c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVES Neuroleptic malignant syndrome (NMS) requires emergency treatment and can be fatal. Combined aripiprazole and clozapine therapy is rarely used in clinical settings, and NMS related this combination still lacks evaluation. Herein, we present two cases of atypical NMS treated with aripiprazole and clozapine. METHODS Case 1 was a schizophrenic male with a history of NMS under treatment with aripiprazole 20 mg. He was hospitalized and maintained with aripiprazole 5 mg and clozapine 225 mg. On the 25th day, atypical NMS occurred with rigidity, elevated creatine kinase, and stupor, which subsided with supportive therapy. He was discharged under treatment with aripiprazole 15 mg and fluoxetine 60 mg. Case 2 was a female with schizoaffective disorder without a history of NMS. She was hospitalized and maintained with clozapine 50 mg and aripirazole 30 mg. On the 11th day, atypical NMS occurred with mild fever, delirium, and rigidity, which subsided under supportive therapy. RESULTS AND CONCLUSIONS Our cases highlight the atypical features of NMS in patients being treated with combined ari-piprazole and clozapine. Consciousness change, modest elevation of creatine kinase, and leukocytosis were the most consistent findings; hyperthermia accounts for only some of the cases. This is a reminder of the importance of earlier detection of the soft signs and atypical features of NMS under this combined treatment.
Collapse
Affiliation(s)
- Ping-Tao Tseng
- Tsyr-Huey Mental Hospital, Kaohsiung Jen-Ai's Home, Taiwan
| | - Yi-Chung Chang
- Tsyr-Huey Mental Hospital, Kaohsiung Jen-Ai's Home, Taiwan
| | - Chih-Hua Chang
- Tsyr-Huey Mental Hospital, Kaohsiung Jen-Ai's Home, Taiwan
| | - Hung-Yu Wang
- Tsyr-Huey Mental Hospital, Kaohsiung Jen-Ai's Home, Taiwan
| | - Yu-Shian Cheng
- Tsyr-Huey Mental Hospital, Kaohsiung Jen-Ai's Home, Taiwan
| | - Ching-Kuan Wu
- Tsyr-Huey Mental Hospital, Kaohsiung Jen-Ai's Home, Taiwan
| | | | - Weilun Chung
- Tsyr-Huey Mental Hospital, Kaohsiung Jen-Ai's Home, Taiwan
| |
Collapse
|
47
|
|
48
|
Ford KA, Ryslik G, Sodhi J, Halladay J, Diaz D, Dambach D, Masuda M. Computational predictions of the site of metabolism of cytochrome P450 2D6 substrates: comparative analysis, molecular docking, bioactivation and toxicological implications. Drug Metab Rev 2015; 47:291-319. [DOI: 10.3109/03602532.2015.1047026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
49
|
Charifson PS, Walters WP. Acidic and Basic Drugs in Medicinal Chemistry: A Perspective. J Med Chem 2014; 57:9701-17. [DOI: 10.1021/jm501000a] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Paul S. Charifson
- Vertex Pharmaceuticals Incorporated, 50 Northern Avenue Boston, Massachusetts 02210, United States
| | - W. Patrick Walters
- Vertex Pharmaceuticals Incorporated, 50 Northern Avenue Boston, Massachusetts 02210, United States
| |
Collapse
|
50
|
Jia LL, Zhong ZY, Li F, Ling ZL, Chen Y, Zhao WM, Li Y, Jiang SW, Xu P, Yang Y, Hu MY, Liu L, Liu XD. The Aggravation of Clozapine-Induced Hepatotoxicity by Glycyrrhetinic Acid in Rats. J Pharmacol Sci 2014; 124:468-79. [DOI: 10.1254/jphs.13257fp] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
|